Fig. 3

SEM micrograph of C. phalacrocoracis metacercaria. a–c Unexposed control group; a fore body tegumental surface exhibited; distinct transverse annulation (ts), first collar-like ring; semicircular shape (1st cr) and second flat shaped (2nd cr), sensory papillae (sp). b A large ventral sucker (vs), ventral spongy fold (vf), sensory dome like papillae (sp). c Hind body exhibited smooth normal tegument without spines (st). d–f Exposed worm to V. alternifolia extract; d oral sucker showed disappearance (ts), desquamated tegument (ds), and disfigured collar-like rings e ventral sucker exhibited thicker vf, disappeared of dome like papillae (dsp) surrounded the ventral sucker. f Hind body exhibited detached and starched tegument (stt). g–i Exposed worm to M. piperita extract; g apical view of oral sucker exhibited; edematous tegument with completely disappeared (tr), collar-like ring (cr) and ejection of blebs (bl). h Ventral sucker showed a thinner ventral fold and ejection of blebs (bl). i Hind body exhibited ejection blebs (bls)